/*
* TI/National Semiconductor LP3943 GPIO driver
*
* Copyright 2013 Texas Instruments
*
* Author: Milo Kim <milo.kim@ti.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2.
*/
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/mfd/lp3943.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
enum lp3943_gpios {
LP3943_GPIO1,
LP3943_GPIO2,
LP3943_GPIO3,
LP3943_GPIO4,
LP3943_GPIO5,
LP3943_GPIO6,
LP3943_GPIO7,
LP3943_GPIO8,
LP3943_GPIO9,
LP3943_GPIO10,
LP3943_GPIO11,
LP3943_GPIO12,
LP3943_GPIO13,
LP3943_GPIO14,
LP3943_GPIO15,
LP3943_GPIO16,
LP3943_MAX_GPIO,
};
struct lp3943_gpio {
struct gpio_chip chip;
struct lp3943 *lp3943;
u16 input_mask; /* 1 = GPIO is input direction, 0 = output */
};
static inline struct lp3943_gpio *to_lp3943_gpio(struct gpio_chip *_chip)
{
return container_of(_chip, struct lp3943_gpio, chip);
}
static int lp3943_gpio_request(struct gpio_chip *chip, unsigned offset)
{
struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
struct lp3943 *lp3943 = lp3943_gpio->lp3943;
/* Return an error if the pin is already assigned */
if (test_and_set_bit(offset, &lp3943->pin_used))
return -EBUSY;
return 0;
}
static void lp3943_gpio_free(struct gpio_chip *chip, unsigned offset)
{
struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
struct lp3943 *lp3943 = lp3943_gpio->lp3943;
clear_bit(offset, &lp3943->pin_used);
}
static int lp3943_gpio_set_mode(struct lp3943_gpio *lp3943_gpio, u8 offset,
u8 val)
{
struct lp3943 *lp3943 = lp3943_gpio->lp3943;
const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
return lp3943_update_bits(lp3943, mux[offset].reg, mux[offset].mask,
val << mux[offset].shift);
}
static int lp3943_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
lp3943_gpio->input_mask |= BIT(offset);
return lp3943_gpio_set_mode(lp3943_gpio, offset, LP3943_GPIO_IN);
}
static int lp3943_get_gpio_in_status(struct lp3943_gpio *lp3943_gpio,
struct gpio_chip *chip, unsigned offset)
{
u8 addr, read;
int err;
switch (offset) {
case LP3943_GPIO1 ... LP3943_GPIO8:
addr = LP3943_REG_GPIO_A;
break;
case LP3943_GPIO9 ... LP3943_GPIO16:
addr = LP3943_REG_GPIO_B;
offset = offset - 8;
break;
default:
return -EINVAL;
}
err = lp3943_read_byte(lp3943_gpio->lp3943, addr, &read);
if (err)
return err;
return !!(read & BIT(offset));
}
static int lp3943_get_gpio_out_status(struct lp3943_gpio *lp3943_gpio,
struct gpio_chip *chip, unsigned offset)
{
struct lp3943 *lp3943 = lp3943_gpio->lp3943;
const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
u8 read;
int err;
err = lp3943_read_byte(lp3943, mux[offset].reg, &read);
if (err)
return err;
read = (read & mux[offset].mask) >> mux[offset].shift;
if (read == LP3943_GPIO_OUT_HIGH)
return 1;
else if (read == LP3943_GPIO_OUT_LOW)
return 0;
else
return -EINVAL;
}
static int lp3943_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
/*
* Limitation:
* LP3943 doesn't have the GPIO direction register. It provides
* only input and output status registers.
* So, direction info is required to handle the 'get' operation.
* This variable is updated whenever the direction is changed and
* it is used here.
*/
if (lp3943_gpio->input_mask & BIT(offset))
return lp3943_get_gpio_in_status(lp3943_gpio, chip, offset);
else
return lp3943_get_gpio_out_status(lp3943_gpio, chip, offset);
}
static void lp3943_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
u8 data;
if (value)
data = LP3943_GPIO_OUT_HIGH;
else
data = LP3943_GPIO_OUT_LOW;
lp3943_gpio_set_mode(lp3943_gpio, offset, data);
}
static int lp3943_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
int value)
{
struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
lp3943_gpio_set(chip, offset, value);
lp3943_gpio->input_mask &= ~BIT(offset);
return 0;
}
static const struct gpio_chip lp3943_gpio_chip = {
.label = "lp3943",
.owner = THIS_MODULE,
.request = lp3943_gpio_request,
.free = lp3943_gpio_free,
.direction_input = lp3943_gpio_direction_input,
.get = lp3943_gpio_get,
.direction_output = lp3943_gpio_direction_output,
.set = lp3943_gpio_set,
.base = -1,
.ngpio = LP3943_MAX_GPIO,
.can_sleep = 1,
};
static int lp3943_gpio_probe(struct platform_device *pdev)
{
struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
struct lp3943_gpio *lp3943_gpio;
lp3943_gpio = devm_kzalloc(&pdev->dev, sizeof(*lp3943_gpio),
GFP_KERNEL);
if (!lp3943_gpio)
return -ENOMEM;
lp3943_gpio->lp3943 = lp3943;
lp3943_gpio->chip = lp3943_gpio_chip;
lp3943_gpio->chip.dev = &pdev->dev;
platform_set_drvdata(pdev, lp3943_gpio);
return gpiochip_add(&lp3943_gpio->chip);
}
static int lp3943_gpio_remove(struct platform_device *pdev)
{
struct lp3943_gpio *lp3943_gpio = platform_get_drvdata(pdev);
return gpiochip_remove(&lp3943_gpio->chip);
}
static const struct of_device_id lp3943_gpio_of_match[] = {
{ .compatible = "ti,lp3943-gpio", },
{ }
};
MODULE_DEVICE_TABLE(of, lp3943_gpio_of_match);
static struct platform_driver lp3943_gpio_driver = {
.probe = lp3943_gpio_probe,
.remove = lp3943_gpio_remove,
.driver = {
.name = "lp3943-gpio",
.owner = THIS_MODULE,
.of_match_table = lp3943_gpio_of_match,
},
};
module_platform_driver(lp3943_gpio_driver);
MODULE_DESCRIPTION("LP3943 GPIO driver");
MODULE_ALIAS("platform:lp3943-gpio");
MODULE_AUTHOR("Milo Kim");
MODULE_LICENSE("GPL");
